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Just installed new model ERDTT switch

39K views 86 replies 36 participants last post by  linkim 
#1 ·
Forum member joesonvolt from Quebec has been working on a new model ERDTT switch as a successor to his original. I’ve been in correspondence with him and a few days ago I received the new model hot off his workbench.

The new version is in the form of a Y cable. The foot of the Y is an I/O switch. The top arms of the Y are a green male connector and a black female connector. The original temperature sensor in the car has an identical green male connector. During installation, this connector is detached and the new Y cable is plugged into the two original male and female connections. There is no need to remove the temperature sensor from its mounting near the radiator. The I/O switch allows either the original sensor or the new resistor to be inline. If the resistor path is used, the outside temperature will read significantly higher than it actually is, deterring the Engine Running Due To Temperature.







The hard part of the installation is accessing the sensor and its connector. One method is to remove the front passenger wheel and then the inside wheel well panel. An alternate way is go from below the car and remove a plastic shield to get to the sensor, and I decided on this method. I’ve never enjoyed laying on a garage floor working on a car whose front end is up on ramps though, so I called up my friendly neighborhood car repair shop and asked if they would let me use one of their lifts and work with me to install the cable. They readily agreed and it took us about twenty-five minutes to raise the Volt, get the shield off, locate the sensor, and install the new cable. Now that we know where everything is, we could probably do it in ten to fifteen minutes.

I routed the I/O cable up through the gas generator space and fastened the switch discretely near the passenger side headlight housing. We are due for a bout of frigid air here in West Michigan over the next few days, so I was glad to get this modification done. Today the outside temperature dropped to 30 degrees, but the dashboard reading showed 56 degrees, so the mod is apparently working.

The quality of the design and build of the cable is high. There are also little extra touches: including zip ties for securing the cable, a dustproof flexible transparent cap for the I/O switch, and even a dab of dielectric grease inside the female connector. The new model switch can be found here:

http://www.ebay.ca/itm/Chevrolet-Volt-Add-on-for-external-temp-sensor-prevent-engine-running-ERDLT-/281495720520?pt=Automotive_Services&hash=item418a73d248&vxp=mtr]

A nod of thanks to forum member ari_c for some helpful hints on installation and forum member somms for his pictures of the sensor location here:

http://gm-volt.com/forum/showthread.php?85874-Any-way-to-stop-the-engine-from-running-so-much-in-the-winter&p=1140098#post1140098

Cheers!
 
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#2 ·
Nice, I went with the 47k ohm resistor in the OAT sensor seems to put the temps up 15 F when it's 30 F outside I'm not in Canada so I only need to worry if it gets below 0 F. Not sure what the difference will be at lower temps.
 
#3 · (Edited)
This whole ERDTT mod baffles me. I guess I drive too many miles in a day to worry about using a bit of gasoline.

I'm far away from modding anything. I just buy 'em and drive 'em anymore.

I leave my ERDTT setting at 30+F (whatever stock is). It came on the last two days and I have no problem with the car working as it was designed. My thinking is: The ICE is there, why not use it?
 
#5 ·
Right! The OCD people have about a engine using .07 (otherwise known as just a hair more than a CUP!) of a gallon when the temperature is freezing is borderline mentally ill.
 
#4 ·
Hold on?

I know ERDTLT doesn't run the engine like 'Hold mode' does, but with the correct resistance values perhaps it could begin to crack that feature? At some point, somebody is going to find the wires that probably send the message that the battery is used up. Whether line resistance, or mil-amps, knowing where they are and how the values change seems like it will happen. There's got to be a simple way to fool the controller into thinking the engine needs to run. Out of warranty, it is only a matter of time.
 
#12 ·
I know ERDTLT doesn't run the engine like 'Hold mode' does, but with the correct resistance values perhaps it could begin to crack that feature? At some point, somebody is going to find the wires that probably send the message that the battery is used up. Whether line resistance, or mil-amps, knowing where they are and how the values change seems like it will happen. There's got to be a simple way to fool the controller into thinking the engine needs to run. Out of warranty, it is only a matter of time.
No need to crack it. You can find the resistor values from part 44034 from here (http://www.omega.com/temperature/Z/pdf/z256-257.pdf). To start the engine you need (for 2011-2012, for 2013+ you already have hold mode) to be above 20.08Kohm (+/- x), engine will run until the coolant temp is at point X. Fake the sensor reading for that also and you get the full hold mode (and prolly burn the engine with coolant over temp).
 
#7 ·
The main thing I have against ERDTT is when it runs the engine when I'm pulling into the garage or a parking spot. Why can't it ask like EMM.
 
#8 ·
Yeah, that's irritating as all get out, isn't it?

As a practical matter, it doesn't. But being practical would have led me to a Mazda2 ...
 
#15 ·
This. On a short drive, you likely do not need the ICE coming on. My car is warm or has been preconditioned. Having the ICE kick in 10 ft after pulling out of the garage is a waste. Having it kick in again just before I park is also a waste. Having it turn on during a long drive is welcome. Give me a switch on the dash.
 
#19 ·
I want to do this because last winter I ended up with rusted cams and cloudy oil after a winter of a four mile commute in cold temperatures. Maybe no cause and effect but I'm not taking any chances. If I get to avoid pumping gas in the cold that's a bonus too. If I want need more heat I can always put the engine in hold mode.
 
#20 · (Edited)
Should the car behave the way the person wants Vs Design and warranty.


First, this isn't to Brag but to clarify my background as an Automotive repair expert.

I have over 25 years experiance in the feild in various capacities. I have worked in the shop, I've taught in the classroom, I've sold parts, I've managed repair shops both as a foreman and a service manager.

I am an ASE certtifed Master tech in both Automotive and Med/Heavy Duty truck. Along with L1 Advanced engine performance, Part specialist and service advisor. I've been published a few times in various tade magizines.


So enough of my resume.


The Volt is by far the most complex machine I have seen. It's incredible that it could even be produced, much less for the cost to the end user.


It's not a "golf cart" like the Tesla is at it's core. It's not a conventional 4 stoke Otto engine thats been the norm basically unchanged for the last hundred years. This drivetrain is unchartered terrain.


So, the engine runs sometimes in a manner that some feel uneeded. Ok. And they might be right........






Or they may not be.





So, lets weigh cost vs risk of unindented consequences.......

For General Motors - They have a bunch of money tied into an entirely new mode of transport. They also must warranty this drivetrain. Great. So they design it, possibly overdesigned to meet consumer expectations. At least MOST consumers. There are going to be some people who dont like it, but you cant please everyone...


Risks to GM

Warranty Costs - They do exisit to make a profit.
Public Opinion - Look at the 80s. People that werent even alive wont buy GM products because of the rep produced from those $hit years.
Loss of R&D money - GM is hedging their bets that this mode of transport will take off. If it doesn't, thats money lost.


Risks to end user.

Damaged vehicle - Yup. Ths can happen. The fact is, this drivetrain design is just too new to learn the full extent of any long term effects from changing the design. And Chevrolet has no obligation to release how the system works to you or anyone outside of their company. They have a obligation to produce a vehicle that operates as designed, and I would say they lived up to that.


"I did it, and had no Ill effects." Really? How would you know. Did you measure all components before assembly, then try your idea and disassemble to measure the wear? Any metalurgy tests? What are you basing your "No problem whateversoever." On.... that the car continues to run? Bravo, very solid science.

But it's under warranty.... Ok, so you dont use the fluids or other sundries the manufacture asks you too or change their design, then it goes south and you expect them to pay? Really? So, if it turns out saving 6 gallons of gas does $6,000 of damage..... you will just open your checkbook or will you demand GM repair the aftermath of your modification...... You did it and they should pay the price for your experiment. I can't start with how wrong that line of thinking is.


Everyone who buys a Volt that I have talked to tends to be smart..........Very smart. And likely has used their smartness to do great things, and wow co-workers, friends and family.

Smartness does have a price though..... I call it the "Arrogance of Intellect", which is smart people think they are smarter than just about everyone else and feel that just looking at the surface of a device, they can do it better then the teams of smart people who deisgned it for years all day every day.


That is an incredibily arrogant mindset that has both created great things, but also destroyed them.


All to save 6 gallons of gasoline and/or be Top Dog on a score keeping website that offers no fiscal reward.


See why I say it's silly?
 
#52 ·
Smartness does have a price though..... I call it the "Arrogance of Intellect", which is smart people think they are smarter than just about everyone else and feel that just looking at the surface of a device, they can do it better then the teams of smart people who deisgned it for years all day every day.
You seem to be advocating that automotive engineers and designers have considered all possible scenarios and can never make mistakes and that vehicles issued by the carmakers are flawless so one should ever attempt to modify them. If that were indeed the case there would never be a need for any automobile recalls.

Working on our cars is a long standing American tradition. For some people it’s half the fun of owning an automobile. I don’t call that arrogance, I call it innovative; taking something good and making it better, or at least more suitable and enjoyable for one’s personal use.

I love my Volt, but there are at least a dozen changes that I have done or am thinking of doing to make it more usable to me. Next on my list after ERDTT – doing something about the rock hard door armrests. The team that worked on designing those all day every day must enjoy sleeping on oak planks at night!
 
#21 ·
Madmike,

This is exactly the situation where avoiding ERDDT is needed with the Volt.
The engine is not needed to have a comfortable cabin and it is bad for the engine.

Of course this duty is bad for any engine.

Hopefully this is addressed on the G2 Volt !
 
#22 ·
The engine is not needed to have a comfortable cabin and it is bad for the engine.

Of course this duty is bad for any engine.

Based on what? What do you know that the teams designers of this brand new drivetrain format didn't discover?

Turning off a regular engine and restarting over and over sure, but this is the most well thought out vehicle ever. Why does it only burn .07 of a gallon? Why not .06? why not .08? Was it jsut random? I doubt it.




It's possible that GM knows more then us about their products.....
 
#23 ·
I agree with Elemental's observations in general. However, Frank Weber (the Volts lead engineer who later moved to BMW to bring out the i3) posted this ERDTT resistance trick after doing it to his own Volt. That was after our own WOT discussed the idea as well. The ICE coming on during ERDTT is strictly for the comfort of the driver and passengers -even if they don't need it. Note that GM has bounced the setpoint of when ERDTT occurs all over the place 30°F, 26°F, 15°F depending on model year. If a newer Volt allows the driver to set the ERDTT at 15°F, why would setting a 2011 to the same be a problem, especially given that the Volt's lead engineer did it by inserting a resistor into the air temperature sensor to have it artificially read a higher outside temp? This is not about the battery drive-train, this is about being able to set your own ERDTT thermostat.
 
#24 ·
Ok, now we have something. This is a modification ny people who DO know what they are talking about. If everything you posted is true (I have no reason to think not) now we have a modification with a manageable risk of unintended consequences.





So, I will now default to OCD craziness.....Which is soley an opinion, not science. :)
 
#25 ·
As a 2012 owner, the thing that might convince me to buy this is a three way switch with low and high resistors. In colder weather that is above the ERDTT threshold in situations where I know I'm going beyond the battery range, I'd like to be able to turn the engine on early for heat, as well as the ability to suppress it for short trips. Trips over 5 or 6 miles but within battery range I probably wouldn't change, personally.
 
#26 · (Edited)




At least on the 2013+ onwards Volts, we do have that big, beautiful DRIVE MODE button we can push anytime on the fly for ICE generated heat via HOLD or MOUNTAIN MODE!:eek:

I agree that it is not so convenient though for those 2011-12 Volt owners that only have MOUNTAIN MODE to select if they want ICE assisted heat!:(



BTW: Fairly certain that ship has sailed long ago concerning whether the popular Ambient Temp Sensor mod is actually harmful to the lith ion battery life as several Volt owners are approaching their 2nd and third winters using this mod w/o anyone reporting negative effects!?:confused:
 
#28 ·
I have version 1.0 installed since last December. I raise my Volt on a pair of ramps. Hardest part of the install was popping the sensor back in the hole. Very difficult. The 2.0 version makes than unnecessary and should be relatively easy in comparison.

I did mine in mid-December and my concrete floor was freezing. Not fun laying on your back on a cold floor trying to pop that sensor in. Almost 1 year and mine is still working great. Car said it was in the high 40s this morning, even though actually it was about 27F.
 
#30 ·
#29 ·
#31 ·
For me it's a matter of being able to pre-warm my 2012 in my driveway without running afoul of my municipality's anti-idling bylaw. I also dislike the ERDTT running on short trips but the pre-warm is my main concern.
 
#32 ·
No Automotive Engineer "intends" a gas engine to turn on for a few minutes on really cold days and never warm up completely.

Plus, when I watched engine temp with the Torque app the engine was not even getting up to a normal ICE operating temp.
It would get up to something like 153° F and then shut off.
 
#33 ·
Good point. No doubt they wanted the ICE to turn off before it got warm enough to open the thermostat that starts the coolant circulating through the radiator, to keep all the heat in the coolant loop. Sounds logical, but I'm not sure it's good for the engine. I'm not an engine expert, though. I thought I remembered someone knowledgeable saying it wouldn't be harmful. Time will tell, I guess.
 
#34 ·
5-46 Instruments and Controls


ENGINE RUNNING DUE TO TEMPERATURE
This message displays when the high voltage battery is charged but the engine has to come on because of the outside temperature or high voltage battery temperature.

Just saying, this is what the owners manual says.
 
#37 ·
The manual is referring to the engine running due to temperature when the battery gets EXTREMELY cold. Like your car sitting in sub zero temps all day long cold. Even when this occurs, the engine does not heat the battery. The battery has it's own separate coolant loop and an electric heating element for this purpose. This only happens to protect the battery when it gets too cold, putting a load on an extremely cold lithium battery is not a good idea. The engine will run continuously allowing you to still drive the car while the TMS warms the battery to a safe temperature. Once the battery is warmed the engine shuts off and all electric driving resumes. This happened to me twice last winter here in Minnesota when we had those insane brutally cold nights. I had the temperature mod in place all last winter and it didn't interfere with this happening. You will not harm your battery with this mod, the battery has it's own temperature sensors and could care less what the modified ambient temperature sensor is reporting.
 
#46 ·
Ambient Light/Sunload Sensor

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.

This sensor assembly provides information about:

• Sun heat intensity
• Passenger compartment temperature

The solar sensor is connected to ground and to a 5 V stabilized voltage supply through the HVAC control module. As the sunload increases, the sensor signal voltage also increases and vice versa. The signal varies between 1.4-4.5 V and is provided to the HVAC control module.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.




Having an offset OAT sensor doesn't seem to effect my HVAC Auto setting. I think the passenger compartment temperature sensor plays a larger role for the interior cabin temp then the OAT does IMHO...
 
#47 ·
Forum member joesonvolt from Quebec has been working on a new model ERDTT switch as a successor to his original. I’ve been in correspondence with him and a few days ago I received the new model hot off his workbench.
Do you know how much he charges S&H to the US? It's not really clear in the listing.
 
#48 · (Edited)
From the listing, $10 worldwide, no? I also used the "Shipping link, added my zip and it said $10

Shipping:
US $10.00 (approx. C $11.32) Standard Shipping | See details

Ships to:
Worldwide
Given the $70 delivered cost, how many years will it take for payback? I have about 3 winter months. My ERDTT is 25°F. I also enjoy having engine heat for longer trips. It's just the short trips to the store that bug me. That means I'd be "popping the hood latch, opening the hood, flipping the switch to spoofing mode, closing the hood" for those short trips on days 25°F or below. And then repeating when I got home to reset the switch from spoofing mode. That hassle and the perhaps dubious economics regarding gas saved gives me pause.

My preference would be a switch inside the car, easily reached, perhaps under the dash in the driver's foot well. And something that did not take many years for payback. YMMV.
 
#50 · (Edited)
I try not to overengineer/overthink these things so I'm more than good with the KISS principle of just putting a small resistor in parallel inside of the stock OAT sensor.

I've had my 47kohm offset sensor installed for going on a year w/o any issue and it is also a very stealth install unlike the other type(s) involving external switches and such...

In the other thread, I actually volunteered to modify any OAT sensor If you could mail it off to me for free since I have the proper wirewrap tool and 1/8 watt tiny resistors to perform this mod. Thus far, I have had exactly 1 taker on this offer!:confused:
 
#51 ·
Or, buy a $4 replacement sensor (add $3 shipping) and mod that. If you you are concerned about being able to return the car to OEM specs simply replace your modded version with the original. Have the replacement part shipped to somms when you buy it. The sensor is the same part number MY 2011-2014 (and likely 2015) "Ambient Air Temperature Sensor - part 25775833"
 
#56 ·
I am in the camp of being annoyed whenever ERDTT comes on. I'd buy this switch & wiring right now, but the eBay listing is no longer current. I sent joesonvolt/joesonebay a message to see if he's going to make or offer any more and will update this with his response.
 
#62 ·
I just installed the ERDTLT override on my 2012 Volt. I removed the skirting near the passanger front wheel and accessed the temperature sensor. After installing the senor, I fished the cable up through the engine compartment and zip-tied the switch to a line near the engine coolant tank.

At first I didn't think it was working. Before I installed the override, the temp on the center screen was reading 39 degrees F. After installing it, the reading was still 39 F. I let the car "run" for a while but the reading remained the same.

I put everything back together and backed off the wheel ramps and went for a drive. Two or three minutes later, the temperature display started to rise, 40, 41, 42 and so on. It stopped at 60, so the offset is ~20 degrees as far as I can tell, although the outside temperature is warmer than my garage this morning.

ERDTLT is the one thing that annoyed me about my Volt. My commute is only 2.5 miles round trip now (used to be 50 miles RT) and with the colder temps here in St. Paul, MN I have been using 0.2 gallons and around 1 kW of battery. Prior to this, I was using 0.6 kW RT.

For me the 70 dollars is well worth not having the engine run.
 
#63 ·
the temperature display started to rise, 40, 41, 42 and so on. It stopped at 60, so the offset is ~20 degrees as far as I can tell, although the outside temperature is warmer than my garage this morning.
The colder it is, the greater the offset. For me, when it was 17F, it reported 51F. Lowest I ever saw it go was maybe 47F last year when it was like -2F.

I would love a full table of the sensor values mapped to F or C so I could accurately calculate the correct temperature. I've seen a listing every 10F from -40 to 60, but the sensor values are not exactly linear.
 
#66 ·
Kind of a delayed update, but I joesonvolt/joesonebay responded to my message by posting another harness on eBay last week that I nabbed up right away. I just received it in the mail yesterday and am quite satisfied with the build quality. He included an extra seal that goes around the male green connector, a few zip ties to secure it underhood, and pre-applied dielectric grease on the connections. I plan on installing it sometime this week during the long holiday weekend. I plan to go from underneath the skirt when I put my car on ramps rather than through the wheel well.

My usage plan with the switch is to only run the bypass resistor when necessary, so I'll be watching the forecast daily when it starts getting cold. I know I'll have to plan a trip ahead before a low temp hits to make sure the sensor adjusts ahead of time.

BTW, it looks like joesonvolt has at least another harness listing active on eBay for people that have been waiting.

http://www.ebay.ca/itm/Chevrolet-Vo...rg=20140620075055&rk=1&rkt=10&sd=281495720520
 
#67 ·
Kind of a delayed update, but I joesonvolt/joesonebay responded to my message by posting another harness on eBay last week that I nabbed up right away. I just received it in the mail yesterday and am quite satisfied with the build quality. He included an extra seal that goes around the male green connector, a few zip ties to secure it underhood, and pre-applied dielectric grease on the connections. I plan on installing it sometime this week during the long holiday weekend. I plan to go from underneath the skirt when I put my car on ramps rather than through the wheel well.
Sounds good. Let us know how it works out for you.

Cheers
 
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